with t1 as (
    select CHECKUP_DATE,MEMBER_CODE,WEIGHT,ROW_NUMBER() OVER(PARTITION BY MEMBER_CODE ORDER BY CHECKUP_DATE DESC ) row_num
    from HEALTH_CHECKUP
)
select a.CHECKUP_DATE as CK_DATE,a.MEMBER_CODE as CODE,c.LAST_NAME||c.FIRST_NAME as NAME, ROUND((a.WEIGHT-b.WEIGHT),1) as CHG_WT
from
(select CHECKUP_DATE,MEMBER_CODE,WEIGHT,row_num
from t1
where row_num =1 ) a,
(select CHECKUP_DATE,MEMBER_CODE,WEIGHT,row_num
from t1
where row_num =2 ) b,
MEMBER_MST c
where a.MEMBER_CODE = b.MEMBER_CODE
and a.MEMBER_CODE = c.MEMBER_CODE
and abs(CHG_WT)>=5
order by CHG_WT desc ,a.MEMBER_CODE desc